1. Field of the Invention
The present invention relates to an apparatus for oral hygiene care, and more particularly, to an apparatus for personal dental care employing ultrasonic energy suitable for regular use in the home.
2. Discussion of the Relevant Art
The art abounds with many different devices designed specifically to provide a means for dislodging food particles which may be retained between the teeth or removing deposits of plaque, tartar and scale occurring on the teeth. Many different types of manual brushing instruments have been invented over the years and finally a mechanical device which increases the number of strokes per second has become very popular with the public. However, the mechanical tooth brush has difficulty reaching the narrow space between the teeth and thus maintain the interproximal areas free of debris, or to remove foreign particles trapped at the gingival crevices i.e., the gum line. The popular motor driven tooth brushes generally operate from the standard 60 cycle (Hz) source or include a rechargeable battery which may be recharged from the 60 Hz source. The motion imparted to the mechanical brush element may be rotary, longitudinal or oscilatory, either in a longitudinal, transverse mode or combinations thereof. Generally, the brush element moves somewhere between 60 and 120 times a second.
These motor driven tooth brushes provide advantages over the conventional manual tooth brush since many more brushing strokes occur per second by the motor driven device. Therefore, for a given amount of time more brushing is performed by the user.
However, the use of these conventional motor driven tooth brushes does not necessarily overcome many of the disadvantages of manual brushing. Although a somewhat increased scrubbing action relative to the manual brushing occurs at the tooth surfaces which come into contact with the bristle ends stains of foreign deposits in the interproximal and gingival crevices or gum line areas are reached no better than by the manual instrument. Accordingly, the cause for many dental cavities and gingival disease are not removed by substitution of a convention motor driven tooth brush with a manually actuated implement.
Many attempts have been made to utilize an ultrasonic driven motor to drive a tooth brush in order to improve the cleaning efficiency and thereby reduce tooth decay. Many ultrasonic cleaning devices are at present available for use in dental offices, however, few, if any, devices are available for use by an individual for personal home dental care.
Many different circuit arrangements have been utilized to provide the ultrasonic energy necessary to activate a tooth brush. Typical of these devices is disclosed in U.S. Pat. No. 3,375,820 issued to Arthur Kuris, et al on Apr. 2, 1968. Typical circuitry is disclosed in U.S. Pat. No. 3,544,866 issued to R. B. McLeroy on Dec. 1, 1970. McLeroy disclosed solid state circuitry for driving the magnetostrictive transducer of an ultrasonic dental tool where the power output to the tool is controlled by variation of the duty cycle rather than amplitude of the ultrasonic output cycle. The signal voltage driving the ultrasonic magnetostrictive transducer is a square wave having a variable pulse width or duty cycle which square wave is amplified in the power amplifier to drive the magnetostrictive transducer. The circuitry disclosed therein is relatively expensive and does not lend itself for use in a personal hand held apparatus to be used for personal oral hygiene.